The present application relates generally to the field of a weather radar system. More specifically, the present application relates to an antenna system for a weather radar system utilizing dual polarization.
Weather radar systems are used to assess weather altitudes and to separate weather from ground clutter at ranges to the horizon. Conventional antenna systems for weather radar systems generally utilize one of vertical polarization or horizontal polarization, but lack the capability to use simultaneous dual polarization. As a result of using a single polarization, the reliability and failure-free operational time of such radar systems can be limited.
Some dual polarization antenna systems are available but place great demands on traditional two-axis mechanically driven flat plate antenna commercial radar systems. As a result, active microwave electronics are required to be embedded to the aperture of the radar antenna system. The use of such active apertures can decrease reliability of radar antenna systems compared to conventional flat plate systems and can significantly increase system cost. Additionally, conventional antenna feed assemblies lack high cross polarization isolation. Poor received signal strength due to cross polarization can result when using a dual polarized antenna system.
Some aircraft use dual radar installations to insure availability of the radar function, but for those systems a single antenna and antenna positioner are generally used. So while the availability of a dual system is offered by the dual receiver/transmitter (R/T), the non-dual elements limit potential gains to availability. Although most antenna elements are very simple and thus very reliable, the switch used to connect either R/T to the antenna is not a dual element and thus represents a function that may limit the potential improved availability of a dual R/T system. A dual antenna system can be used with each R/T connected to its own antenna except that the typical space allocated to the radar function precludes the use of two separate antennas.
Therefore, there is a need for a simultaneous dual polarization antenna system and method. Furthermore, there is a need for radar system with high cross polarization isolation. Yet further, there is a need for an antenna architecture with increased reliability. Yet further still, there is a need for an antenna system for a weather radar or radar-based terrain avoidance and warning system that utilizes simultaneous or near simultaneous dual polarization. Even further, there is a need for an active radar antenna that exploits two independent orthogonal polarizations to achieve high (higher MTBF) availability weather radar systems, mean time between failures.